The present invention relates to an inspection apparatus and an inspection method.
In an inspection method for inspecting a wiring substrate configured by arranging wiring on a substrate, there is a method to perform a test by a so-called continuity check, that is, by supplying a current through a test probe or the like to positions where wiring is disposed and determining whether the current is received from other positions.
However, in the inspection method by the continuity check, in a case where a wiring substrate includes a plurality of independent wiring patterns and a short circuit is detected therebetween, it is necessary to fix one end of the probe to one arbitrary wiring pattern and electrically connect the other end of the probe to all other wiring. Furthermore, such an operation needs to be performed on all independent wiring patterns, and the inspection method is very complicated.
Therefore, in the inspection of the wiring substrate, an inspection method has been reviewed which inspects a continuity or the like of a wiring by measuring an electric capacitance between a wiring and an electrode such as a ground (GND) and comparing a magnitude of the obtained electric capacitance with an expected value (see, for example, Japanese patent publications S53-10863 and 2008-218443).
However, in the related art inspection method for inspecting the wiring substrate by measuring the electric capacitance, in a case where the electric capacitance between the wiring and the electrode such as GND is very small, even when a wiring is disconnected in the middle, it is difficult to detect the disconnection.
For example, recently, a through wiring substrate technology, such as a Through Silicon Via (TSV) technology or a Through Glass Via (TGV) technology, has attracted attention in the fields of wiring substrates.
For example, the TSV technology is one of semiconductor packaging technologies and uses a through silicon via (TSV) that vertically passes through the inside of a semiconductor chip made of silicon or the like. Similarly, the TGV technology uses a through glass via (TGV).
In the past, in a case where a plurality of semiconductor chips is overlapped and accommodated in one package, electrical connection between the stacked semiconductor chips is achieved by using a wire bonding technology. In contrast, for example, the TSV technology performs electrical connection between the stacked semiconductor chips by a TSV. The use of the TSV technology can eliminate the necessity of a wiring space for wire bonding. Therefore, in a case where the TSV technology is used, a semiconductor package with three-dimensionally mounted chips can be made smaller and thinner as compared with the related art.
In the semiconductor packaging technology using such TSV technology, it is important that a TSV vertically passing through a semiconductor chip being a base body is formed to have a desired characteristic. Therefore, in the semiconductor chip or the like in which the TSV is formed, an inspection for detecting the existence or non-existence of disconnection of the TSV is required.
In a silicon chip with a TSV, the TSV can be regarded as a plurality of mutually independent wiring. The silicon chip in which the TSV is formed can be regarded as a wiring substrate including a plurality of mutually independent wiring. Therefore, in the inspection in which the silicon chip with the TSV is an inspection object, as described above, it is desirable to apply the inspection method for inspecting the wiring substrate by measuring the electric capacitance.
However, in the case of the silicon chip with the TSV, since the substrate being the base body is thin and a conductive material such as a metal for configuring the TSV is little, the electric capacitance formed between the TSV and other electrode is small. Therefore, in the inspection by the measurement of the electric capacitance, even when the TSV being the wiring is disconnected in the middle, it is difficult to detect the disconnection.
Therefore, there is a need for a technology that can inspect a disconnection or the like of a wiring by measuring an electric capacitance of an inspection object such as a silicon chip with a TSV. That is, for an inspection object including a base body made of silicon or glass and a wiring passing through the base body, there is a need for a technology that can inspect the disconnection or the like of the wiring by measuring the electric capacitance even in the case where, since the base body is small, the wiring passing through the base body is also small and the electric capacitance of the wiring to be inspected is small.
The present invention has been contrived in consideration of such problems.
That is, the purpose of the present invention is to provide an inspection apparatus that can inspect an inspection object by measuring an electric capacitance even in a case where an electric capacitance of a wiring of the inspection object is small.
Further, the purpose of the present invention is to provide an inspection method that can inspect an inspection object by measuring an electric capacitance even in a case where an electric capacitance of a wiring of the inspection object is small.
The other objects and advantages of the present invention become clear in the following description.